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【单选题】

Dolphins (海豚) live their whole lives in water. But they are mamma& (哺乳动物J) that live in water. That’ s why a dolphin comes to the top of the water so often. A dolphin’ s nose isn’ t easy to see. It’ s just a tiny hole on top of the dolphin’ s head. This hole is called a blowhole. A dolphin comes up every half minute or so to breathe. It opens its blowhole and takes in air. Then it closes its blowhole tight and dives into the water again. But a dolphin can stay under the water for six or seven minutes if it has to. It holds its breath.
A dolphin hears with two ears. It hears all sorts of small noises under water. It hears small stones rolling. It can hear sounds fish and other dolphins make. A dolphin’s ears may be extra small, but its mouth is extra big. It has to be big. It holds almost one hundred teeth. These teeth are all the same shape and size. They are used for catching food, but not for chewing (咀嚼) it. A dolphin opens its big mouth. It seizes (抓住) a fish firmly between its two rows of teeth. Then it swallows (吞下) the whole fish.
A dolphin swims very fast. It is said that a dolphin swims faster than anything else in the water. So engineers are studying its skin and shape. They are learning ways to make boats go faster through the water.
It is well known that dolphins are very smart. Some scientists say they are smarter than dogs. Others say they are smarter than apes (类人猿).
A dolphin breathes through its ______.

A.
month
B.
ears
C.
skin
D.
blowhole
题目标签:类人猿海豚
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【单选题】类人猿型骨盆的特点是

A.
骨盆各径线均较正常小2cm
B.
骨盆3个平面横径均缩短,前后径稍长,坐骨切迹宽
C.
两侧骨盆壁向内倾斜
D.
骨盆入口肾形,骶骨下段后移,入口前后径明显缩短
E.
骨盆入口前后径缩短,横径正常

【单选题】类人猿骨盆

A.
入口略呈三角形,骶坐切迹窄呈高弓形
B.
入口横径较前后径稍长,骶坐切迹呈圆形
C.
入口横径较前后径短,骶坐切迹较宽
D.
入口横径较前后径长,骶坐切迹较宽
E.
入口横径较前后径短,骶坐切迹较窄